Over the last 25 years, a sustained and marked decline in death rates from coronary heart disease (CHD) has occurred for all major segments of the U.S. population. Recently, however, the decline has proceeded less rapidly in blacks than in whites, and in women than men. These trends have focused further attention on possible heterogeneity in the risk factor patterns among the demographic sub-groups. Previous studies of CHD risk factors in blacks and whites using the First National Health and Examination Survey Epidemiologic Follow-up Study (NHEFS-l, 11-year follow-up), including this group's own work, demonstrate its potential strengths, while at the same time foundering on the problem of low statistical power. With the extension of the follow-up of NHANES-l cohort (1971-1974) to 1987 (14 years) and the completion of 14-year follow-up for NHANES ll cohort (1976-1980), a strong rationale exists to undertake a "pooling project." The resulting data set would provide optimal characterization of CHD risk at the national level. This application proposes to accomplish three principal aims. First, they will determine whether or not the two samples can be effectively pooled. To accomplish this aim, they will assess the distribution of baseline measures and determine whether the same logistic prediction equations fit both studies. Second, they will examine gender-race differences in individual exposure-outcome relationships, patterns of co-morbidity, and population attributable risks. Finally, the fully documented data file will be made available for public use via the Internet.